1. Field of the Invention
The present invention relates to composite structures in which an inorganic layer is joined to an organic layer.
2. Description of the Related Art
The fabrication of multilayer materials can pose manufacturing challenges, and the resulting constructions may exhibit performance limitations, where different types materials are joined at an interface. This is particularly so in the case of constructions having an inorganic material, such as a metal or metal compound, joined to an organic (e.g., polymeric) material. The abrupt transition between layers having very different physical properties, such as stiffness and rates of heat transport, and chemical compositions can compromise their anchorage to one another--a critical performance requirement in many applications--as well as the durability of the inorganic layer. For example, because inorganic and organic materials typically have very different coefficients of thermal expansion and elastic moduli, even perfectly adhered inorganic layers may undergo failure (e.g., fracturing) due to temperature variations or stress during manipulation and ultimate use. The different responses of two adjacent layers to an external condition can easily cause damage that would not occur in either layer by itself.
To improve interlayer anchorage, polymeric layers may be selected (or applied as intermediate coatings) based on chemical compatibility with inorganic material. A polymeric layer may also be pretreated (e.g., through plasma exposure) to modify the surface for greater interfacial compatibility with a subsequently applied inorganic layer. These approaches, however, have limited utility in addressing the effects of transition between fundamentally different materials.